Sandstone 'Carpet Rock' - Morocco - (ref CP042290.5)

Actual Piece

Measurements approximately

Length 6.6cm

Width 4.5cm

Depth 1.3cm

Weight 90.5g

Sandstone ‘Carpet Rock’  from Morocco displaying Liesegang rings. Sometimes these appear as box-shaped and triangular patterns. 

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These patterns are abundant in sandstone from this area and are formed when Iron minerals such as Hematite or Pyrite in the sandstone oxidise because water has permeated the sandstone dissolving the iron minerals into a solution and subsequently erosion has exposed the iron mineral solution to oxygen in the atmosphere. 

The oxidised solution precipitates between the layers of sandstone, finding tiny crevices where joints exist and form the different colour bands within the rock giving the patterns ,often in polygonal shapes, which lead to the name "Carpet Rock”.

A similar effect occurs when Quartz forms harder zones in sandstone which resist erosion such as the sandstone from Petit Jean Set Park in Conway County, Arkansas USA.

  
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